1. Field of the Invention
The present invention relates to a navigation system for guiding a mobile unit such as a vehicle.
2. Description of the Related Art
Recently, among vehicles such as passenger cars, the number of vehicles on which a navigation apparatus is mounted is increasing. The navigation apparatus provides information for assisting driver's driving, such as a map and a recommended route. Specifically, a navigation apparatus reads out map data which are previously recorded as digital data on a recording medium in a vehicle such as a CD-ROM, a DVD-ROM, or a hard disk drive, from the recording medium, and displays a map on a display device on the basis of the map data. In response to an operation by the driver, moreover, the navigation apparatus calculates a guide route from the current location to a destination on the basis of a predetermined algorithm, and displays the calculated guide route on a the map displayed on the display device.
Some of conventional navigation apparatuses for a vehicle calculates a difference route between the guide route displayed on the display device and the actual travel route of the vehicle, and then conducts a learning process to reflect a result of the learning process into the next guide route, thereby providing a guide route suitable to the intention of the user (For example, see JP-A-9-287970, JP-A-2000-193473 and JP-A-2002-310699.).
Another navigation apparatus has been proposed which receives a result of a route search calculated by a large host computer disposed in the outside, and displays a guide route on a display device on the basis of the received route search result (See JP-A-2002-340594.).
JP-A-9-287970, JP-A-2000-193473, JP-A-2002-310699 and JP-A-2002-340594 are referred to as related art.
At the present, in a navigation system, a navigation apparatus disposed in a vehicle is operated to display a map and guide a route. By contrast, it is expected that, in the future, the function of communicating with a vehicle terminal or a personal computer in a house (hereinafter, referred to as home PC) is enhanced and therefore a navigation apparatus in a vehicle and the home PC are connected to communicate each other.
However, there is no framework for conducting communication between the home PC and the navigation apparatus to display a guide route, and causing the home PC to conduct a learning process on the basis of the difference between the displayed guide route and the actual travel route. Therefore, the home PC cannot conduct a route search in accordance with the taste of the user.